In a graph database, data is represented and stored using graph structures including, for example, vertices and edges. For instance, the vertices of a graph may correspond to the individual data items stored in a graph database while the edges of the graph may define the relationships between various data items. The vertices and the edges of the graph may be associated with various properties (e.g., weights, costs, distances, and/or the like) that further describe individual data items as well as the relationships between various data items. Thus, relationships between data items are stored explicitly (e.g., as edges and one or more corresponding properties) in a graph database.
By contrast, a relational database is configured to store relationships between data items implicitly. In a relational database, data is organized into tables (e.g., relations) that contain data items sharing one or more of the same attributes. Each data item in a table may be associated with a key. Here, a relationship between data items residing in different tables is implicitly defined by cross-referencing the respective keys of the data items. For example, one table may include the keys of related data items from another table, thereby linking data items from two different tables. Alternately and/or additionally, a relational database may provide tables for storing the keys of related data items from separate tables.